On Tue, 16 Jul 2002, Davi Leal wrote:
> > > P.D.: Do you know if sendmail uses only 25/tcp?. /etc/services does not
> > > shows any 25/udp.
sendmail uses TCP:25 (optionally also 587{msa} and 465{smtps}) only...
> > The version of sendmail I'm running 8.12.1-5 listens on tcp port 25 and
> > also TCP port 587. For details regarding port 587 use, take a look at
> > /usr/share/doc/sendmail/RELEASE_NOTES.gz and also RFC 2476. Port 587 is
> > used to run a Message Submission Agent which is turned on by default.
Correct... you *can* make 587 available only to localhost:
FEATURE(`no_default_msa')dnl
DAEMON_OPTIONS(`Family=inet, Name=MSA-v4, Port=587, M=E, A=127.0.0.1')dnl
> > As far as I know, sendmail doesn't listen on any UDP ports.
again, correct
> Maybe, I'm not sure, some remote MTAs, for example smtp.navegalia.com, uses
> UDP connections. You can try "telnet smtp.navegalia.com 25" behind a
> firewall which filter the udp connection.
Eh?
$ telnet smtp.navegalia.com 25
Trying 212.73.32.155...
Connected to smtp.airtel.net.
Escape character is '^]'.
220 ESMTP service
It answers TCP, I know of no MTA (or MUA) that uses UDP...
If you're having firewall problems then most likely:
*) TCP port 25 is not allowed
*) TCP port 113 (AUTH) is not allowed (it should be REJECTED, a
DROP will result in some remote MTA timeouts as they try to
issue AUTH requests)
--
Rick Nelson
<Mercury> emacs sucks, literally, not a insult, just a comment that its
large enough to have a noticeable gravitational pull...
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